1 # SPDX-License-Identifier: GPL-2.0-only
3 # RCU-related debugging configuration options
12 bool "RCU list lockdep debugging"
13 depends on PROVE_RCU && RCU_EXPERT
16 Enable RCU lockdep checking for list usages. By default it is
17 turned off since there are several list RCU users that still
18 need to be converted to pass a lockdep expression. To prevent
19 false-positive splats, we keep it default disabled but once all
20 users are converted, we can remove this config option.
27 tristate "performance tests for RCU"
28 depends on DEBUG_KERNEL
33 This option provides a kernel module that runs performance
34 tests on the RCU infrastructure. The kernel module may be built
35 after the fact on the running kernel to be tested, if desired.
37 Say Y here if you want RCU performance tests to be built into
39 Say M if you want the RCU performance tests to build as a module.
40 Say N if you are unsure.
42 config RCU_TORTURE_TEST
43 tristate "torture tests for RCU"
44 depends on DEBUG_KERNEL
49 This option provides a kernel module that runs torture tests
50 on the RCU infrastructure. The kernel module may be built
51 after the fact on the running kernel to be tested, if desired.
53 Say Y here if you want RCU torture tests to be built into
55 Say M if you want the RCU torture tests to build as a module.
56 Say N if you are unsure.
58 config RCU_REF_SCALE_TEST
59 tristate "Scalability tests for read-side synchronization (RCU and others)"
60 depends on DEBUG_KERNEL
65 This option provides a kernel module that runs performance tests
66 useful comparing RCU with various read-side synchronization mechanisms.
67 The kernel module may be built after the fact on the running kernel to be
70 Say Y here if you want these performance tests built into the kernel.
71 Say M if you want to build it as a module instead.
72 Say N if you are unsure.
74 config RCU_CPU_STALL_TIMEOUT
75 int "RCU CPU stall timeout in seconds"
76 depends on RCU_STALL_COMMON
80 If a given RCU grace period extends more than the specified
81 number of seconds, a CPU stall warning is printed. If the
82 RCU grace period persists, additional CPU stall warnings are
83 printed at more widely spaced intervals.
85 config RCU_EXP_CPU_STALL_TIMEOUT
86 int "Expedited RCU CPU stall timeout in milliseconds"
87 depends on RCU_STALL_COMMON
92 If a given expedited RCU grace period extends more than the
93 specified number of milliseconds, a CPU stall warning is printed.
94 If the RCU grace period persists, additional CPU stall warnings
95 are printed at more widely spaced intervals. A value of zero
96 says to use the RCU_CPU_STALL_TIMEOUT value converted from
97 seconds to milliseconds.
100 bool "Enable tracing for RCU"
101 depends on DEBUG_KERNEL
102 default y if TREE_RCU
105 This option enables additional tracepoints for ftrace-style
108 Say Y here if you want to enable RCU tracing
109 Say N if you are unsure.
112 bool "Provide debugging asserts for adding NO_HZ support to an arch"
113 depends on DEBUG_KERNEL
115 This option provides consistency checks in RCU's handling of
116 NO_HZ. These checks have proven quite helpful in detecting
117 bugs in arch-specific NO_HZ code.
119 Say N here if you need ultimate kernel/user switch latencies
120 Say Y if you are unsure
122 config RCU_STRICT_GRACE_PERIOD
123 bool "Provide debug RCU implementation with short grace periods"
124 depends on DEBUG_KERNEL && RCU_EXPERT && NR_CPUS <= 4
126 select PREEMPT_COUNT if PREEMPT=n
128 Select this option to build an RCU variant that is strict about
129 grace periods, making them as short as it can. This limits
130 scalability, destroys real-time response, degrades battery
131 lifetime and kills performance. Don't try this on large
132 machines, as in systems with more than about 10 or 20 CPUs.
133 But in conjunction with tools like KASAN, it can be helpful
134 when looking for certain types of RCU usage bugs, for example,
135 too-short RCU read-side critical sections.
137 endmenu # "RCU Debugging"